Question

我在初学Java类中，只是学习数组的概念。我们必须使用注释来表示代码。

我正在尝试创建一个程序，要求用户输入20个数字，将它们存储在一个数组中，然后计算并显示：最小数字，最高数字，数字总数和数字平均值。

通过jGrasp运行时出现了大量错误，我不确定如何修复它们。

有什么建议吗？

public class NumberAnalysisProgram
{
  public static void main (String[] args)
  {


  Scanner input = new Scanner (System.in);

  //A constant for the array size
  final int SIZE = 20;

  //Declare an array to hold the numbers entered by the user
  int[] numbers = new int[SIZE];

  //Declare variables to hold the lowest and highest
  int lowest = numbers[0];
  int highest = numbers[0];

  //Declare variable to hold the total
  int sum;

  //Declare a variable to hold the average
  double average;

  //Declare a counting variable to use in the loops
  int index = 0;

  //Explain the program
  System.out.println("This program gets a list of 20 numbers. Then displays:");
  System.out.println(" the lowest number, the highest number, the total of the numbers,     
  and the average.");

  //Get the numbers from the user
  for (int i = 0; i< numbers.length; i++)
  {
  System.out.print("Please enter 20 numbers, each seperated by a space:  ");
  numbers[i] = input.nextInt();
  }


  //Call a method to calculate the lowest and highest numbers
  getLowHigh(numbers);

  //Display the lowest and highest numbers
  System.out.println("The lowest number is:  " + lowest);
  System.out.println("The highest number is:  " + highest);



  //Call a method to calculate the total of the numbers
  sum = getTotal(numbers);

  //Display the sum/total of the numbers
  System.out.println("The total of these numbers are:  " + sum);



  //Call a method to calculate the average of the numbers
  average = getAverage(sum, numbers);

  //Display the average of the numbers
  System.out.println("The average of these numbers are:  " + average);

 }


  //Method getLowHigh
  public static int getLowest(int[] array)
  {
     for(int i=1; i< numbers.length; i++)
     {
          if(numbers[i] > highest)
          highest = numbers[i];
       else if (numbers[i] < lowest)
       lowest = numbers [i];
     }

     return highest;
     return lowest;   
  }

  //Method getTotal
  public static int getTotal(int[] array)
  {

  //Loop counter variable
  int index;

  //Accumulator variable initialized to 0
  int total = 0;

  //Pull in the numbers from the main method to calculate the total
  for(index = 0; index < numbers.length; index++)
  {
     total = total + number[index];
  }

     return total;  
  }

  //Method getAverage
  public static int getAverage(int[] array)
  {

     //Loop counter variable
     int index;


     //Pull in the sum and the numbers from the main method to calculate the average
     for(index = 0; index < numbers.length; index++)
     {
        average = sum / number[index];
     }

     return average;  
   }
}

Answer 1

我能看到的第一个问题是，在所有方法中，你从未使用过这些参数。您使用了不同的数组，这些数组在这些方法中不存在。

第二个问题是你试图从一个方法返回两个值。您只能从方法返回一个值。所以你必须摆脱“return highest;”并复制没有“return lowest;”的方法，并在需要的地方使用。

我看到的第三件事（虽然没有造成任何错误）是你可以通过说

来缩短代码

int total = 0;

for(int index = 0; index < numbers.length; index++)
{
   total += number[index];
}

而不是

int index;

int total = 0;

for(index = 0; index < numbers.length; index++)
{
   total = total + number[index];
}

Answer 2

对于初学者，下面的代码试图将变量初始化为不存在的数组值......这些应该完全删除。

//Declare variables to hold the lowest and highest
  int lowest = numbers[0];
  int highest = numbers[0];

下面的代码中也会出现这些错误，因为您没有将它们传递给函数，因此它在此范围内不存在。 public static int getLowest（int [] array） { for（int i = 1; i＆lt; numbers.length; i ++） { if（numbers [i]＆gt;最高）最高=数字[i]; 否则如果（数字[i] <最低）最低=数字[i]; }

     return highest;
     return lowest;   
  }

您还为一个只调用一个的函数提供了2个参数。见下文：

//Call a method to calculate the average of the numbers
  average = getAverage(sum, numbers);

public static int getLowest(int[] array)
  {
     for(int i=1; i< numbers.length; i++)
     {
          if(numbers[i] > highest)
          highest = numbers[i];
       else if (numbers[i] < lowest)
       lowest = numbers [i];
     }

     return highest;
     return lowest;   
  }

Answer 3

我认为这更干净：

public class Main {
    public static final int SIZE = 20;

    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        List<Integer> numbers = new ArrayList<Integer>();

        Double total = 0d;

        System.out.println("This program gets a list of 20 numbers. Then displays:");
        System.out.println(" the lowest number, the highest number, the total of the numbers, and the average.");

        // Get the numbers from the user
        System.out.print("Please enter 20 numbers, each seperated by a space:  ");
        for (int i = 0; i < SIZE; i++) {
            Integer currInput = input.nextInt();
            numbers.add(currInput);
            total += currInput;
        }

        System.out.println("The lowest number is:  " + Collections.min(numbers));
        System.out.println("The highest number is:  " + Collections.max(numbers));
        System.out.println("The total of these numbers are:  " + total);
        System.out.println("The average of these numbers are:  " + (total / SIZE));

    }
}

希望它有所帮助：]

数字分析程序

3 个答案: